If a student can make what ___has been learned , whether in class or from social practice,he will make steady progress.
_________ he was, he still went on with his work.
It is ten years since we ________ each other last time.
More wild tigers have been seen in the forest around this area, ________ there used to be very few.
It is usually warm in my hometown in March, but it ________ be rather cold sometimes.
You can never be ________ when crossing the street.